Conventionally, the comparison of two words is performed with a carry-propagation subtractor. The subtraction is performed bit-by-bit. The carry occurs in a bit-by-bit sequence.
A disadvantage of this known solution is that the number of word bits to be compared is high, and the subtraction takes time.
Another disadvantage of this known solution is that it is slow and requires a large number of transistors.
The use of a parallel subtractor to reduce the carry-propagation time has also been proposed. The disadvantage of this alternative is that it considerably increases the complexity of the circuit, i.e. the number of transistors.